114 



If, oil the other baud, the members of either family are compared with 

 those of others here admitted, which have been combined with them, 

 the differences will be found to be much more radical, and this remark 

 applies in the highest degree to the two forms respecting which the old 

 and superficial ideas are most persistent, that is, the Talpidse and 

 Chrysochloridse. The external similarity as to form in these groups is 

 great. The osteological and dental differences are greater than between 

 any other forms of the suborder Bestice. 



I.— CONTRASTED CHAEACTERS OFSORICID.E A:N^D TALPIDSE. 



SKULL. 



{Teeth.) 



SOKICIDJE. I TALPID^. 



Teeth of upper jaw: 



M. 3, Pm. 1-2, C. 1, 1.2-4x2; 



Teeth of upper jaw : 



M. 3, Pm. 3-5, C. 1, 1. 2-3 x 2 ; 



true molars mostly — i. e., M. 1 and M. 2 — with four primary (but gener- 

 ally reduced to three by coalescence of the median) external and two 

 primar^r and more elevated internal cusps; the outer and inner connected 

 together by oblique ridges, and thus circumscribing two re-entering 

 triangular areas pointed inwards; with an internal ledge bearing a 

 cusp along its inner wall ; 



also with a well-developed sec- 

 ondary lower ledge behind the prin- 

 cipal internal one. 



Teeth of lower jaw: 



M. 3, Pm. 1-2, C. 1,1.1x2. 



True molars with two primary 

 external cusps — i. e., anterior and 

 posterior — and four primary inter- 

 nal cusps — i. e., an anterior, two me- 

 dian — (the posteromedian some- 

 times coalescent with the antero- 

 imedian), and a posterior; 



the antero-external cusp connected 

 ■with the anterior and antero-me- 

 dian internal by ridges, and thus 

 circumscribing a triangular area ; 



the postero-external cusp con- 

 nected with the posterior internal 

 cusp and with the ridge near and 

 from the antero-internal to the me- 

 dian internal cusp, thus defining a 

 trapezoidal area : 



but with no (well-developed) sec- 

 ondary lower ledge behind the prin 

 cipal internal one. 



Teeth of lower jaw: 



M. 3, Pm. 3-5, 0. 1, 1. 3-1 x 2. 



True molars with two primary 

 external cusps — i. e., anterior and 

 posterior — and three primary inter- 

 nal cusps — i. e., an anterior, an an- 

 tero-median — (the postero-median 

 being suppressed), and a posterior; 



the antero-external cusp connected 

 with the anterior and antero-me- 

 dian internal by ridges, and thus 

 describing a triangular area ; 



the postero-external cusp connected 

 with the posterior internal as well 

 as with the median or postero-me- 

 dian internal by ridges, and thus 

 circumscribing a triangular area: 



Premolars, canines, and incisors varying greatly among the Talpid£e, 

 but little among the Soricidce. 



